Smartscan - Resolving issues gives message "The online content is unavailable"

After doing a Smartscan I found no virusses but there were a few issues. I want to resolve these issues. The “Updating outdated software” step worked fine. The next step of “Resolving performance issues” however does not work. After I click “resolve all” I get the message “The online content is unavailable. Please, check your internet connection and try again.”

There is nothing wrong with my internet connection though - it works fine for everything else. How do I resolve this issue?

Related to Avast Cleanup, which is a paid product.